The Motion Pictures Expert Group (MPEG) has promulgated the MPEG audio and video standards for compression and decompression algorithms to be used in the digital transmission and receipt of audio and video broadcasts in ISO-11172. The MPEG audio standard provides for the efficient compression of data according to an established psychoacoustic model to enable real-time transmission, decompression and broadcast of CD quality sound. The MPEG audio standard provides for three possible modes of data transfer. The first mode is audio and visual data plus information to be used to synchronize the broadcast of the audio and video portions. The second mode of possible data transmission involves audio information and information that can be used to synchronize the audio information with a video system. The third and final mode of possible data transmission comprises only audio data.
The first two modes of MPEG data transmission provide information in the bit stream to synchronize the bit stream and specify the rate at which the decoded bit stream is to be presented to the listener. The MPEG standard provides for a variety of bit rates and sampling rates. If the data is decoded and presented at a different rate than the rate at which the data was encoded, either underflow or overflow of the decoded data can result. Either of these conditions can result in errors in the output audio signal.